Scarborough Village Water Hardness & Quality Report (2026)

Toronto Water serves Scarborough Village as part of the City of Toronto's municipal system, supplying over 3 million residents across the Greater Toronto Area. The water originates primarily from Lake Ontario, drawn through two main intake cribs: the Island and Eastern intakes. Treatment occurs at the R.C. Harris Water Treatment Plant, which serves eastern areas including Scarborough, and the F.J. Horgan Plant. These facilities employ filtration, chlorination, and ammonia for disinfection before distribution via extensive underground mains.

The Lake Ontario watershed spans 73,000 km², with bedrock largely composed of Ordovician Queenston Formation shales. Overlying these are Georgian Bay Formation limestones. These carbonate-rich geological layers are a key factor in the water's mineral profile, as they leach calcium and magnesium into the supply. Glacial deposits, including limestone erratics, further contribute to mineral dissolution, resulting in water that is typically moderately mineralised to hard, unlike softer sources found in the northern shield regions.

This moderately hard water can lead to scale buildup in appliances like kettles, pipes, and fixtures, potentially reducing hot water heater efficiency by up to 20-30% and shortening the lifespan of various household machines. Dishwashers, washing machines, and coffee makers are particularly susceptible to mineral deposits, which can cause spots on glassware and affect laundry quality. Homeowners might consider monthly vinegar descaling for taps and showers, along with annual heater flushes. A water softener is often recommended to mitigate these effects and prevent soap scum, thereby extending plumbing longevity.